5 ms·

That is not correct. In order to fully charge a cell in 5 minutes, you need to charge that cell at 12C. That is just not possible with lithium batteries. 5C is

by diego 5y ago

That is not correct. In order to fully charge a cell in 5 minutes, you need to charge that cell at 12C. That is just not possible with lithium batteries. 5C is pushing it. There is nothing to optimize, you would have to change the battery chemistry. Everything else you mentioned is irrelevant, we are talking about all cells being charged at the same time which is really the only way that makes sense. There is no point in waiting to charge cells.

jatone 5y ago
those are implementation details around the particular batteries. which is fine. nothing I said is absolving us of physical requirements. my point was entirely the system itself as a whole. there are a number of ways to pluck the chicken. smaller more numerous cells -> same power, faster charging due to concurrency. point was if your cable can't supply the power the entire point is irrelevant.
- magicalhippo 5y ago
  > smaller more numerous cells -> same power, faster charging due to concurrency Not really, because smaller cells -> less capacity -> lower current for same C rating. One 1000 mAh battery charging at 5C means 5A charging current, while two 500 mAh batteries in parallel leads to 2 * 2.5A = 5A. And AFAIK typically a larger battery scales better, that is, less dead space for connectors/housing etc so more mAh per volume.
  - jatone 5y ago
    facepalm the assumption being made in my statement is that the individual cell can support the same charging rate. my understanding was it was the chemistry of the cells that impacts the charging rate, not the physical size. happy to be wrong on that though. scaling has mean dimensions. whats best for energy density may not necessarily be best for charging rates.
    - diego 5y ago
      You don't seem to understand what "charging rate" means. There is nothing magical about subdividing lithium cells. No matter the size of the cell, you can't insert energy at a higher rate per unit of volume.

by diego 5y ago

jatone 5y ago

those are implementation details around the particular batteries. which is fine. nothing I said is absolving us of physical requirements. my point was entirely the system itself as a whole. there are a number of ways to pluck the chicken. smaller more numerous cells -> same power, faster charging due to concurrency. point was if your cable can't supply the power the entire point is irrelevant.

magicalhippo 5y ago
> smaller more numerous cells -> same power, faster charging due to concurrency Not really, because smaller cells -> less capacity -> lower current for same C rating. One 1000 mAh battery charging at 5C means 5A charging current, while two 500 mAh batteries in parallel leads to 2 * 2.5A = 5A. And AFAIK typically a larger battery scales better, that is, less dead space for connectors/housing etc so more mAh per volume.
- jatone 5y ago
  facepalm the assumption being made in my statement is that the individual cell can support the same charging rate. my understanding was it was the chemistry of the cells that impacts the charging rate, not the physical size. happy to be wrong on that though. scaling has mean dimensions. whats best for energy density may not necessarily be best for charging rates.
  - diego 5y ago
    You don't seem to understand what "charging rate" means. There is nothing magical about subdividing lithium cells. No matter the size of the cell, you can't insert energy at a higher rate per unit of volume.